Knicks fans, who filled parts of Barclays Center in Brooklyn, wanted no part of the 19-year-old Porzingis, booing loud and long after his name was called by commissioner Adam Silver.
"Lot of fans weren't happy they drafted me," Porzingis said. "I have to do everything in my hands to turn those booing fans into clapping fans. I was happy about it. Want to be part of this organization. The fans are harsh sometimes. That's how it is in New York, and I'm ready for it."
The Knicks hope to use the 7-foot-1 Porzingis and their approximate $27 million in cap space to rebuild after a disastrous 2014-15 season. New York won just 17 games in Jackson's first full season as team president.
"We need [someone] athletic and to make a real difference in the way we play," Jackson said. "This young man is an eye-opening athlete and player, and so that's something we have to go with."
Porzingis averaged 10.7 points, 4.8 rebounds and one block in 33 games for Cajasol Seville in the Spanish league during the 2014-15 season. He also averaged 11.6 points, 4.1 rebounds and 1.2 blocks for Cajasol Seville in 16 Eurocup games.
He has a strong outside shot, but scouts wonder about his ability to adapt on the defensive end.
"He shoots it with great ease," Jackson said. "He fits very well into what we like to run."
Porzingis worked out for the Knicks on Monday. The workout was cut short due to a cramp but Jackson said the Knicks were impressed by what they learned during Porzingis' work with the trainers and medical staff.
"We went through some of the stringent testing we do, to see what level of athleticism he brings to this and what's his growth potential," Jackson said of Porzingis. "We think there's going to be a good chance he makes rapid improvement, but we do know there's going to be a maturation process."
The Knicks considered trading the pick, but the offers were contingent on which players were selected ahead of them, Jackson said.
"Those things fell the way they did. We had what we wanted and we went with it," he said.
Jackson acknowledged that the Knicks would have to be patient with Porzingis.
"The risk is great but the reward is great, too," Jackson said in an interview with ESPN's Chris Broussard.
This is the Knicks' first top-five pick since 1986, when they selected Kenny Walker with the fifth pick.
Porzingis is the fourth international player chosen by the Knicks in the first round. Their last international first-round pick was Danilo Gallinari (No. 6) in 2008.
Thursday's pick was Jackson's first first-round pick since he took over as president of the Knicks in March 2014.
He was asked whether he felt any concern over his legacy when making the Porzingis pick.
"That's not my thought process," he said. "My thought process is what do I do best for this franchise at this particular time in the history and where we're at."
Information from The Associated Press and ESPN Stats & Information contributed to this report.